1. Field of the Invention
The present invention relates to a construction for a cam rotation sensor attaching portion where a cam rotation sensor is attached which detects rotation angles of camshafts supported on cam holders.
2. Description of the Related Art
A fuel injection engine is provided with a sensor for detecting the rotation angle or angles of a camshaft or camshafts for synchronizing the operation timings of injection valves with the rotation angles of the camshaft or camshafts. Japanese Patent Unexamined Publication No. Hei. 4-287841(JP-A-4-287841) discloses a construction in which a cam rotation sensor is attached to a cylinder head cover.
According to the above conventional construction, however, the cylinder head cover is connected to a cylinder head via a seal member comprising a soft rubber material or the like which is interposed between the head cover and the cylinder head, and therefore, the sensor is liable to be affected by vibrations of the engine. Additionally, no high assembling accuracy is required for assembling the head cover to the cylinder head, and therefore, when attempting at improving the positioning accuracy of the sensor relative to the camshaft or camshafts, this leads to another drawback that an extra cost has to be involved.
The invention was made with a view to solving the problems inherent in the prior art, and a primary object thereof is to provide a construction for a camshaft rotation sensor attaching portion which can facilitate the improvement in positional accuracy relative to camshafts.